The main objective of the proposed research is to further elucidate the role of calcium in cholinergic stimulation of amylase from salivary glands. Accumulated evidence suggests that secretion is dependent on the level of cytoplasmic calcium made available from the extracellular fluid and/or from intracellular storage depots; increases in cytoplasmic calcium initiate the secretory process. The proposed studies will be aimed at examining the contribution of extracellular calcium and calcium derived from internal stores to the release of amylase from mouse parotid glands. The effects of the cholinergic agonist, carbachol, on 45Ca influx and efflux from parotid fragments will be determined and correlated with amylase release. The adrenergic agonist, isoproterenol, will be examined since this agent also stimulates amylase release but does not appear to require extracellulr calcium. Adrenergic agonists utilize cyclic-AMP as an "intracellular messenger". During cholinergic stimulation of amylase release there is an increase in cyclic-GMP (c-GMP) levels in salivary tissue. The relationship between changes in cytoplasmic calcium levels and the levels of c-GMP brought about by use of inhibitors of calcium influx and by the calcium ionophore, A23187. 45Ca fluxes across isolated secretory granules will be examined to determine the possible contribution of the secretory granule as a calcium storage depot.